Remote control of repeaters



REMOTE CONTROL OF REPEATERS I/ Filed June 11. 1926 MTORNEY Patented Dec. 17, 1929 UNITED STATES PATENT OFFICE EDMUND R. TAYLOR, OF NEW YORK, N. Y.,

ASSIGNOR TO AMERICAN TELEPHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK REMOTE CONTROL OF REPEATERS Application filed June 11,

This invention relates to remote control systems, and particularly to arrangements for remotely controlling the gain of a plurality of amplifiers each located at a repeater station.

It is often desirable to control the gain of a plurality of amplifiers from a point remote from said amplifiers.

A common ex- K ample of this is the cord circuit repeater system where the gain of a plurality of amplifiers must be controlled at a toll switchboard,

each amplifier being often located in a re- 3 peater room which is located at a point a considerable distance from a toll switchboard.

Accordingly this invention comprises means for simultaneously controlling the gain of a plurality of amplifiers by means of a control device remote from said amplifiers, the apparatus required to carry this out being comparatively inexpensive.

One embodiment of this invention is shown herein merely for the purpose of illustration. In this embodiment of the invention two transmitting media interconnect a control staing circuit connected to another of the trans mitting media whenever it becomes desirable to increase the gain of the amplifier. At each amplifier station a plurality of relays are provided which are operated by the currents flowing over the signaling circuits connected to the transmitting media. These relays become electrically responsive successively in one direction when direct current and pulses of current flow over the signaling circuits through the corresponding transmitting media in order to increase the gain of each amplifier, and these relays become electrically responsive successively in the other direction when pulses of current flow in one signaling circuit through its associated transmitting medium and no current flows in the 1926. Serial No. 115,402.

other signaling circuit, in order to decrease the gain of each amplifier. Moreover, a plurality of indicating lamps are provided at each repeater station to show at any time the state of the gain adjusting means at that station.

' While the nature of the invention will be pointed out with particularity in the appended claims, the invention itself both as to its objects and features will be better understood from the detailed description hereinafter following when read in connection with the accompanying drawing showing one embodiment of the invention, which comprises a control station I, and two repeater stations I and I the amplifiers at these repeater stations being controlled from the control station 1,.

In the drawing there will be found a control device at the control station 1,. This control device comprises three conductors E, E and E over which pass arms A, B and C respectively. The arm A is mounted on a shaft D, one end of the arm A moving over taps 06 inclusive, and the other end of the arm A moving over the conductor E. Taps 1, 3 and 5 are connected to one side of a transmission path ML conductor E being connected to the other side of the transmission path ML,. The taps 0, 2, 4 and 6 are isolated from the transmission path ML. The arm B is also mounted on the shaft D and is rigidly connected mechanically to the arm A so that these arms A and B move together but are electrically insulated from one another. The other arm C is also mounted on the shaft D and is so arranged that it drives arms A and B. WVhen the arm C is rotated in a clockwise direction it (arm C) makes electrical contact with arm B, thereby closing the transmission path ML Yet when the arm C is rotated in a counterclockwise direction, it is insulated from the arm B thereby maintaining the transmission path ML open.

For the sake of convenience, the apparatus at only one of the repeater stations I will be described herein in detail, the apparatus at I being the same as that at I A relay S is located at the repeater station I in series with a battery B and the transmission path ML,. As the arm A of the control device at the control station I moves in either direction, pulses of direct current pass through the winding of the relay S causing it to become energized and deenergized alternately. A relay SR is also located at the repeater station and is in series with the battery B and the transmission path ML Inasmuch as the transmission path ML becomes closed only when the arm C is rotated in a clockwise direction, the winding of the relay S will therefore become energized only when the arm C is rotated in a clockwise direction. This embodiment of the invention is so arranged that when it is desired to increase the gized and deenergized.

energized and deenergized.

A plurality of resistances R to R inclusive, are connected across the input circuit P of the amplifier A. \Vhen the gain of the /amplifier A is to be increased, the input of the j'amplifier is connected across more of these resistances, and vice versa, when the gain tot the amplifier is to be decreased, the input of the amplifier is connected across fewer of these resistances. A plurality of relays S to S inclusive are located at the repeater station. These relays become successively responsive in one direction when the gain of the amplifier is to be increased and become successively responsive in the opposite direction when the gain of the amplifier is to be decreased. Relays S to S inclusive, correspond. respectively, to resistances R to R inclusive. A plurality of indicating lamps L to L inclusive, are also located at the repeater station, these lamps corresponding, re spectively, to relays S to S inclusive.

hen arm A is on tap 0, the relay S is deenergized and relay S. is either energized or deenergized, depending upon whether or not the arm C makes electrical contact with the arm B. The armatures 1 and 2 of the relay S are normally closed, and remain closed, until current flows through the winding of the relay S The input of the amplifier A is short-circuited through the armature 1 of the relay s hen the arm A moves in a clockwise direction and makes electrical contact with tap 1, relays S and S become energized, attracting their respective armatures. Accordingly, current flows from battery 13, through the winding of a relay S conductor 12, the indicating lamp L,, the winding of the relay S armature 2 of the relay S and ground. Yet before armature 2 of the relay S opens its contact because of the flow of current through the winding thereof, armature 3 of the relay S closes its contact, locking the winding of the relay S to ground through the conductor 15. When armature 1 of relay S closes its contact, the input of the amplifier A is connected across the resistance R thereby increasing the gain of the amplifier as soon as the armature 1 of the relay S opens its contact.

When the arm A moves in a clockwise direction toward tap 2, and opens its contact with tap 1, the winding of the relay S becomes deenergized and the winding of the relay S remains energized. The current now flows from the battery B through the winding of the relay S conductor 11, the indicating lamp L the winding of the relay S the armature 2 of the relay 8,, conductor 14: and ground. By virtue of the make-beforebreak feature of the armatures of relay S the winding of the relay S becomes locked by the armature 3 of the relay S through conductor 15 before the armature 2 of the relay S opens its contact. WVhen the armature 1 of the relay S closes its contact, the input or the amplifier A becomes connected across the resistances R and R thereby in creasing the gain of the amplifier.

hen the arm A moves further in a clockwise direction and makes electrical contact with the tap 3, the winding of the relay S becomes energized and the winding of the relay S remains energized. Current then flows from battery B through the winding of the relay S conductor 12, the indicating lamp L the winding of the relay S armature 2 of the relay S conductor 13 and ground. Armature 3 of the relay S connects ground to the winding of the relay S through conductor 15 before armature 2 of the relay c opens its contact. By the closure of the contact associated with armature 1 of the relay S resistances R to- R inclusive, are connected to the input of the amplifier A, thereby increasing the gain of the amplifier.

lVhen the arm A moves in a clockwise direction away from tap 3 and toward tap 4, the winding of the relay S becomes deenergized and the winding of the relay S remains energized. Current now flows from battery B through the winding of the relay S the conductor 11, the indicating lamp L,, the winding of the relay S}, the armature 2 of the relay S conductor 14 and ground. Armature 3 of the relay S. connects ground to the winding of the relay S through conductor 15 before armature 2 of the relay S opens its contact. By the closure of the contact associated with armature 1 of the relay S resistances R, to R inclusive, are connected to the input of the amplifier A.

lVhen the arm A moves beyond tap 4 in a clockwise direction and makes electrical contact with tap 5, the winding of the relay S becomes energized and the winding of the relay S remains'energized. Current flows from battery B; through the winding of the relay 8,, conductor 12, the indicating lamp L the winding of the relay S armature 2 of the relav S conductor 13 and ground. Armature 3 of the relay S connects ground to the winding of the relay S through conductor 15 before armature 2 of the relay S opens its contact. By the closure of the contact associated with armature 1 of the relay S resistances R to R inclusive are connected to the input of the amplifier A.

- As the arm A moves away from tap 5 in a clockwise direction, the winding of the relay S remains energized while the winding of the relay S becomes deenergized. Consequently current flows from the battery B through the winding of the relay S conductor 11, the indicating lamp L the winding of the relay S the armature 2 of the relay S conductor 14 and ground. Armature 3 of the relay S connects ground to the winding of the relay S6 through conductor 15 before the armature 2 of the relay 8, opens its contact.

By the closure of the contact associated with the armature 1 of the relay S all of the re sistances R to R inclusive, are connected to the input of the amplifier A, so that the amplifier A may operate at its maximum gain.

Thus, it has been seen that as the arm A of the control device at the control station I moves in a clockwise direction, the winding of the relay S is energized, while the winding of the relay S becomes energized and deenergized alternately. The relays S to S,; are progressively responsive in a downward direction connecting one or more of the resistances R to R inclusive, to the input of the amph- .fier A, thereby increasing the gain of the am- When the arm A moves in a counterclockwise direction, the arms B and G at the control station T are insulate-d from each other so that the circuit which includesthe battery B the winding of the relay S and the transmission path ML is opened, the windlng of the relay S becoming deenergized. When the arm A is at or near tap 6, the winding of the relay S is deenergized, so that current flows from the battery B through the winding of the relay S conductor 11, the indicating lamp L the winding of the relay S armature 3 of the relay S conductor 15 and ground. The input of the amplifier A is then connected across all of the resistances R to R inclusive, as has already been shown.

When the arm A moves in a counterclockwise direction and makes electrical contact with tap 5, the winding of the relay S becomes energized, while the winding of the relay S remains deenergized. Current now flows from Battery B, through the winding of the relay Sn, conductor 12, the indicating lamp L the winding of the relay S armature 3 of the the amplifier A is connected across the resistances R to R inclusive.

When the arm A moves in a counterclockwise direction away from tap 5 and toward tap 4, the winding of the relay S becomes deenergized and current flows from the battery B through the winding of the relay S conductor 11, the indicating lamp L the winding ofthe relay S armature 4 of the relay S conductor 17 and ground. Armature 3 ofthe relay 3, connects ground to the winding of the relay S through conductor 15 before armature 4 of the relay S opens its contact. The armature 1 of the relay S. closes its contact shortly before the armature 1 of the relay S opens its contact. Thereafter the input of the amplifier A is connected across the resistances R to R inclusive.

As the arm A continues in a. counterclockwise direction and makes contact with tap 8, the winding of the relay S becomes energized so that current flows from the battery B through the winding of the relay S conductor 12, the indicating lamp L the winding of the relay S armature 4 of the relay S conductor 16 and ground. Armature 3 of the relay 3,. connects ground to the winding of the relay S through conductor 15 before armature 4 of the relay S opens its contact. The armature 1 of the relay 8, closes its contact shortly before the armature 1 of the relay 3, opens its contact and the input of the amplifier A is connected across resistances R to armature 3 of the relay S connects ground to the winding of the relay S through conductor 15 before armature 4 of the relay 8, opens its contact. The armature 1 of the relay S closes its contact shortly before the armature of the relay S opens its contact and the input of the amplifier A is connected across the resistances R and R As the arm A moves in a counterclockwise direction away from tap 1, the windings of the relays S and S are both deenergized, and the winding of the relay S becomes deenergized because no current flows through the winding of that relay from the battery B Consequently the armature 1 of the relay S closes its contact, putting a short circuit on Lil the input of the amplifier A. Thus, it is seen that the relays S to S inclusive, are progressively responsive in the opposite direction as pulses of direct current are transmitted over the transmission path ML As these relays become successively energized, one or more of the resistances R to R inclusive, are disconnected from the input of the amplifier A so that the gain or" this amplifier is decreased.

It is to be specially noted that the control of the gain of a plurality of amplifiers each at a repeater station takes place by means of a control device located at a remote station, the control being eitected by the transmission of direct current over one transmission path and pulses of direct currentover another transmission path, to operate a plurality of relays at each repeater station, the apparatus at one of these stations being shown herein in detail merely for the sake of illustration. lVhen the gain of the amplifiers at the repeater stations are to be simultaneously increased, the control device at the control station is moved in one direction, and when the gain of the amplifiers at the repeater stations is to be decreased, the control device is moved in the opposite direction. Moreover, indicating devices provide means for quickly determining the state of the gain adjusting means at each repeater station.

It is to be understood that while in the em bodiment of the invention shown herein two transmission paths are provided between the control station and each repeater station, over which are transmitted direct current and pulses of direct current, respectively, to effect simultaneous changes in the gain of a plurality of amplifiers, it is within the scope of this invention to provide only one transmission path in place of the two shown herein, the control of the gain adjusting means at each repeater station taking place by the transmission of alternating currents at different frequencies, or by the use of current reversals well known in the art.

hile the invention has been shown and described in one particular embodiment, it is to be distinctly understood that the general principles of this invention may be embodied in other and widely varied organizations without departing from the spirit of the invention and the scope of the appended claims.

What is claimed is:

1. A system for simultaneously controlling the gain of a plurality of repeaters, each of which is located at a repeater station, comprising a station remote from the repeater stations at which there is a controlling device, a. transmitting medium between said remote station and said repeater stations over which two characteristic impulses may be transmitted controlled by said control device, one characteristic impulse consisting of pulsations of direct current, the other characteristic impulse consisting of pulsations of direct current and steady direct current, and means at each repeat/er station responsive to said impulses to change the gain of the repeater thereat.

2. A system for simultaneously controlling the gain of a plurality of amplifiers, each of which is located at a repeater station, comprising a station remote from said repeater stations, a control device at said remote station, a transmitting medium between said remote station and said repeater stations over which two characteristic impulses may be transmitted controlled by said control device, one characteristic impulse consisting of pulsations of direct current, the other characteristic impulse consisting of pulsations of direct current superimposed upon steady direct current, a plurality of relays at each repeater station electrically responsive in one direction to increase the gain of the amplifier thereat and electrically responsive in the other direction to decrease the gain of the amplifier thereat.

3. A system for simultaneously controlling the gain of a plurality of repeaters, each of which is located at a repeater station, comprising a station remote from the repeater stations at which there is a control device, a transmitting medium between said remote station and said repeater station over which two characteristic impulses may be transmitted controlled by said control device, one characteristic impulse being represented by pulsations of direct current, the other characteristic impulse being represented by a combination of pulsations of direct current and steady direct current, means at each repeater station responsive to said impulses to change the gain of the repeater thereat, and means for indicating the state of the latter gain adjusting means.

at. A system for simultaneously controlling the gain of a plurality of repeaters, each of which is located at a repeater station, comprising a station remote from the repeater station at which there is acontrol device, a transmitting medium between said remote station and said repeater stations over which characteristic"impulses may be transmitted controlled by said control device, one of the characteristic impulses comprising pulsations of direct current, another of the characteristic impulses comprising the combination of steady direct current and pulsations of direct current, a plurality of relays at each repeater station electrically responsive in two directions to alternately increase and decrease the gain of the repeater thereat, and a plu-; rahty of mdlcatmglampsone associated with; each relay, said indicatlng lamps indicating the state of the gain adjusting means.

5. A system for simultaneously controlling the gain of a plurality of repeaters each QdfdtArepeater station, comprising a sta tion remote from the repeater station at which there is a control device, two transmitting mgdia between said control statiori and each repeater'station over which characteristic impulses may be transmitted, the characteristic impulse transmitted over one of the transmitting media consisting of pulsations of direct currefitflhe characteristic impulse transmitted over the other of the transmitting media consisting of pulsations of direct current as well as steady direct current, a plurality of relays at each repeat/er station, said relays being responsive in one direction to characteristic impulses to increase the gain of the repeater thereat, said relays being responsive in the other direction'to characteristic impulses to decrease the gain of the repeater thereat.

6'. In a transmission system, a control station, a repeater station, two transmitting media interconnecting said control station and said repeater station, means for generating pulses of direct current for transmission over one of the transmitting media, means for generating steady direct current and pulses of direct current for transmission over the other of the transmitting media, gain adjusting means at said repeater station, a control switch at the control station controlling the transmission of pulses of direct current over one transmitting medium and steady direct current and pulses of direct current over the other transmitting medium, thereby controlling the gain of the repeater at the repeater station.

7. In a transmission system, a. plurality of repeater stations, a control station, a transmitting medium interconnecting the control station and the plurality of repeater stations, gain adjusting means at each repeater station, a control switch at the control station, said control switch simultaneously controlling the gain adjusting means at each repeater station, said control switch transmitting direct current and pulses of direct current as the gain at each repeater station is to be increased, said control switch transmitting pulses of direct current as the gain adjusting means at each repeater station is to be decreased, and step-by-step means at each repeater station responsive to the transmission of said pulsations to simultaneously control the gain adjusting means at each repeater station.

8. In a transmission system, a, luralit of repeater st at i o ns, a control station, a .trans i'mttihg medium interconnecting saidhcontrol station and said repeater stations, gainadjusting means at each repeater station, a switch atthe control station for controlling the gain adjusting means at each repeater statioiifmeans responsive to themanipula tion of the switch in one directionto trans mit pulses of direct current over the transmitting medium, means responsive to the manipulation of the switch in the other direction to transmit steady direct current and pulses of direct current over the transmitting medium, a plurality of relays at each repeater station for controlling the gain adjusting means thereat, said relays being responsive in one direction to increase the gain of the repeater thereat, said relays being responsive in the other direction to decrease the gain of the repeater thereat, and means at each repeater station for indicating the state of the gain adjusting means thereat.

In testimony whereof, I have signed my name to this specification this 10th day of June, 1926.

EDMUND R. TAYLOR.

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